Methods of texturizing filaments



April 6, 1965 E, A. TAYLOR, JR 3,176,373

METHODS OF TEXTURIZING FILAMENTS Filed Dec. 12, 1960 3 Sheets-Sheet 1INVENTOR. ERNEST A TA YLOR,JR

FIG. 3 BY/4%?! ATTORNEY E. A. TAYLOR, JR

METHODS OF TEXTURIZING FILAMENTS April 6, 1965 3 Sheets-Sheet 2 FiledDec. 12, 1960 FIG. 4.

0? xe v7 2 5 o" .020" .040" .060" .080" .noo" J20" J40" CLEARANCEBETWEEN ORIFICE AND ROLL INVENTOR. ERNEST A. TA YLOR,JR wf ATTORNEYUnited States Patent 0 3,176,373 METHODS OF TEXTURlZlNG FlLAPvlENTrlErnest A. Taylor, .lr., Decatur, Ala, assignor, by mesne assignments, toMonsanto (Zompany, a corporation of Delaware Filed Dec. 12, 195i), Ser.No. 75,299 6 Claims. (Cl. 28-72) This invention relates to methods oftexturizing filaments and more particularly to methods of dillerentiallytexturizing synthetic textile filaments or fibers.

It is a well known fact that it is necessary to textnrize or crimpman-made fibers which are to be cut into staple. The reason for this isthat it is necessary to provide some fiber characteristics which willresist longitudinal movement of one fiber relative to another. Withoutthis characteristic the staple fibers would slide too easily along eachother in the assembled yarn, thereby resulting in a yarn of very littletensile strength. Natural fibers such as wool have an inherent crimp orcurl which provides a good frictional engagement between adjacentfibers. However, man-made fibers, which are inherently straight, must betreated in some way to impart good frictional characteristics. It isalso necessary to treat continuons-filament, man-made fibers to givethem better covering characteristics, greater stretchability and abetter hand.

One method of so treating synthetic textile fibers is to texturize orcrimp the fiber. The crimping is usually accomplished by passing aheated tow of filaments between a pair of gears, the teeth of the gearsimparting a wavy configuration to the thermoplastic filaments. Thisarrangement has several disadvantages. One of these disadvantages isthat, due to the physical limitations on gear teeth sizes, it is notpossible to obtain a crimp of very small size. The same is true wheresmooth crimping rolls are used. Another disadvantage is that a pair ofgiven crimping gears cannot be used to obtain a crimp of various sizes.By crimp size, we mean generally the amplitude and length of the wavyconfiguration imparted to the filaments by the crimping operation.

A further disadvantage of conventional gear crimping operations is thatthese operations cannot produce a tow in which the filaments arecompletely looped, i.e., where the slack filament configuration definesa series of loops rather than a wave configuration.

Other types of crimping or texturizing operations involve pulling theyarn across a knife edge or twisting the yarn and then heat setting it.The disadvantage of these types of texturizing operations is that theapparatus has limited life or is not conducive to high speed operation.In crimping operations where rolls feed the yarn into a hot stufiing boxthe high heat duration is likely to result in poor dye uniformity.

With these problems in mind, one of the objects of this invention is toprovide a novel and improved method for treating a filament.

Another object of this invention is to provide a novel method ofimpartin a crimp or curl to a filament.

A f rther object of this invention is to provide a method fortexturizing a thermoplastic filament wherein the amount of crimp or curlimparted to the filament can be later varied by heat treatment of thefilament.

Still another object of this invention is to provide a method oftexturizing a filament by differentially heat ing the filament.

Yet another object of this invention is to provide a method oftexturizing a filament by heating one side of the filament while coolingthe other side thereof.

A method illustrating one embodiment of the invention comprises passinga thermoplastic fiber filament under tension through a zone where oneside of the filament ice is cooled while the other side thereof isheated to a temperature sufficient to soften or plasticize the heatedside. The heated side of the filament will be stress-relieved while itis in the heated condition. The cooled side of the filament, however,does not attain the temperature necessary to accomplish this. Thefrequency and amplitude of the resulting crimp or curl is a function ofthe temperature that the heated part of the yarn attains, thetemperature of the cool side of the yarn, and the ten sion on the yarn.

When tension is removed from the fiber filament the stress-relieved sidedoes not contract, while the other side, which has retained itselasticity, does contract. This pulls the filament into a series oftight coils, the diameter of which is determined by the degree of stressrelief in the heated side of the filament. This series of coils actuallyforms a helix which coils first one way and then the other, since thefilament does not actually twist longitudinally.

in a method illustrating the principles of the invention in greaterparticularity, a thermoplastic filament under tenison is wrapped roundand advanced by a rotating roll which is relatively cool. A narrowstream of heated gas is directed from a nozzle onto the filament to heatthe exposed side thereof to a temperature suificient to soften that sideof the fiber. The cool roll in contact with one side of the fila ientserves as a heat sink to prevent a temperature rise in this side, whilethe temperature of the exposed side is elevated, the actual temperaturebeing determined by the temperature of the gas and speed of thefilament. This stress-relieves one side of the filament while leavingthe other side unchanged. Thus, when tension is removed from thefilament it curls up into a series of tight coils which define a helicalconfiguration. NaturaLy, when a yarn having several individual filamentsis treated by this process the yarn is bulked considerably.

Other objects and advantages of the invention will become apparent whenthe following detailed description is read in conjunction with theappended drawing, in which:

FIGURE 1 is a side view of apparatus for performing a texturizingoperation in accordance with the principles of the invention;

FZGURE 2 is an enlarged view showing a nozzle used to direct heated aironto a filament to be texturized;

FXGURE 3 is an end view of the air nozzle of FIGURE 2 showing the flowpaths of the heated gas;

FlGURE 4 is an enlarged cross-sectional view of a heat-sink roll overwhich the yarn is passed during the operation;

FIGURE 5 is a graph showing yarn bulkiness in terms of the spacing ofthe nozzle relative to the heat-sink roll carrying the yarn; and

FIGURES 644 are graphs showing results of runs made in accordance withthe principles of the invention.

Referring now in detail to the drawings, FIGURE 1 shows apparatus forcarrying out the invention. A thermoplastic yarn 11 consisting of one ormore individual filaments is advanced from a supply bobbin 12 past atensioning device 14 of a conventional type to a heatsink roll 17 whichis driven in a well known manner. The yarn is wrapped one turn aroundthe roll 17 and then advanced to a driven takeup roll 18 of aconventional type.

A nozzle 21 positioned adjacent to the roll 17 directs a stream ofheated gas from a source 22 onto the yarn 11. The nozzle 21 ispositioned very close to the yarn ll so that the exposed sides of theindividual filaments are heated to or near the softening or meltingpoint of the thermoplastic material so that these exposed sides arerelieved of inherent stress. Since the yarn 11 is under tension on theroll 17, it will be flattened and spread so that the individualfilaments are both exposed to the heated gas and in contact with theheat-sink roll 17. The occasional loss of contact of a filament with theroll due to crossed filaments does not, seemingly detract from,

Texturizing Filaments, may be made of stainless steel 7 and isprovidedwith a rectangular opening 23 through which heated air or othergas is directed onto the yarn.

The nozzle is positioned so that the long axis of the rectangularopening 23 is'transverse or perpendicular to the path of travel of theyarn. A typicalnozzle may'have an outside diameter of A inch, arectangular orifice 0.015" x 0.125, and be spaced 0.008" from thesurface of the heat-sink roll 17. V p

FIGURE 3 shows the flow pattern of heated air leaving the opening ororifice 22 and passing between the end of the nozzle and the roll 17.From this it can be seen that the major portion of the heated air flowsin a direction parallel to the yarn path. The flow pattern is determinedby both the clearance between the end of the orifice and the peripheryof the roll, and by the shape and position of the exit orifice. Thisflow pattern does not disturb the positioning of the individualfilaments of the yarn as a transverse air current would. V

The reason for'this unexpected air flow pattern is not fully understood,but it is believed that at points B (FIG;

the orifice 22, while, beyond points A, well defined.

streams of airare flowing away from-the orifice.

The roll 17, vwhich is shown in detail in FIGURE 4, is secured to adriving shaft 26 'and'positioned adjacent to a manifold 27 which has anair intake opening 28 and an air exhaust opening 29. The roll 17 isprovided It has been demon-,-

here refers to the difference in length of the treated fila ment betweena fully extended state and a relaxed state) obtained by various nozzlespacings. The yarn used was 115 denier, 34 filament nylon which wasmoved past the nozzle described above at a rate of 150 feet per minute.

, The air pressure used was 25 psi. and the air temperature was 920 F.with a draw 'ratioof 2.42. 'From the graph 'it can be seen that, withthis particular set of conditions,

i the best bulking was obtained at a nozzle spacing of about 0.008 Underthese conditions, including variations in nozzle size and orifice sizeandspacing, other nozzle spacings may be more desirable.

Depending upon roll size, speed, material, and the quantity of heatedgas impinging upon its surface, it may not benecessary that the roll 17actually be cooled.

Excellent bulking has been obtained'when the roll 17 was kept barelywarm to the touch-apparently about 90 F. The exact upper} limit of drawroll temperature is not known, since it has not been possible toactually measure the temperature of the rotating roll. However, if the'surfaceof the roll becomes too warm there is a pronounced decrease inthe degree of texturizing or bulking.

- The roll temperature should bekept low enough that little .or nostress-relief occurs in the cooler side of the yarn.

Only a small part of the heat expended goes into the roll 17, most of itremaining in. the gas exhausted from the nozzle. The gas, since it doesnot cling to the roll and the yarn as a wetting liquid would, adequatelyheats the exposed side of the yarn without :overly heating the roll orthe filaments in the yarn. A liquid heating medium would probablysurround and adhere to the filaments of the yarn to heat substantiallyall of each filament. This would'not achieve the desired result, whichis basedon heating one side of the filament while main- 1 taining theother side at a relatively low temperature.

with a face plate32 and a plurality of intake cooling However, anon-wetting liquid such as molten solder might be used for heating theexposed side of the yarn.

The periphery. of the roll 17 would extend intoa pool only the exposedside of the yarn.

The air temperature andpre'ssure and the yarn speed are variableswhichare dependent upon each other, given a nozzle spacing and size. FIGURES6-14 serve as examples to show bulking or texturizingobtained when haustopening in the manifold27. This cools the roll 17 so that it' serves asa heat sink or heat absorber to keep one side of each of the individualfilaments of the yarn 11 relatively cool as the other side isheated.

Factors which affect the yarn bulking ortexturizing operations are airtemperature, spacing of the nozzle from the roll, air supply pressure,yarn speed, yarn tension, and draw roll temperature. The amount of heatthat must be applied to the exposed side of the fiber will 7 vary inaccordance with the softening or. melting point of the fiber. Thus, afiber having a relatively low .melt

ing point will not require as much heat for bulking as will a highmelting point fiber. Since it is very difficult to actually determinethe yarn temperature, the process is best carried out by controlling theair'press'ur'e and temperature to give the desired result on theparticular.

FIGURE 5 shows the results of runs made to determine; 7

the perecent of yarn bulking (the term bulking as used these threefactors are varied. These runs were made using the above-describednozzle spaced 0.008" from the roll 17,'the yarn being denier, 34filament nylon. Of course, the yarn ca n be run at lower speeds thanshown in ,FIGS.6- 14. by using lower air temperatures, or at higherspeeds by using higher air temperatures. Also, monofilaments can betreated with equal success.

The yarn treated by this process can be used in any application wherebulkexi or texturized yarn is desired. In addition, this yarn can beused to make nonwovens of widely varying characteristics.

' These unique nonwovens are formed by winding the bulked ortexturized'yarn, under tension, onto a takeup roll of a desirable size,as shown in FIGURE 1. After a sufiicient layer of yarn is wound onto thetakeup roll, the roll is stopped and the yarn layer is cutlongitudinally and removed from the roll. This removes the tension from'the yarn so that it may contract freely. As the bulked filamentscontract (i.e., assume their texturized configuration) the filamentsform coils and loops that interlock with'the coils of adjacentfilaments, thereby forming a mat or batt of intimately associated,interlocked filaments.

The size, thickness and textureof the batt formed by been texturizedwith equal success.

this method depends upon the degree of texturizing or bulking of theyarn. For example, a layer of highly bulked yarn was wound under tensiononto a bobbin having a circumference of approximately inches, the yarnbeing traversed onto the bobbin at a low helix angle. When the yarnlayer was cut longitudnally it contracted to a width of about 2 inches(from the original 10 inches). The edges and sides of the batt weresmooth and rounded and no loose ends of the severed filaments werevisible. In fact, it was impossible to find the loose ends merely byvisual inspection. The individual filaments in this batt were helical inconfiguration, with a helix diameter of about 0.05 inch. A 1 length ofyarn, when relaxed, would have 7-8 loops. A length of yarn extending, inits relaxed state, a distance of 1" might contain 60 to 80 loops. Thelongitudinal length of the yarn layer changed very little, while thecircumferential length decreased approximately 80% and the thickness ofthe batt increased 10 to 12 times.

These nonwoven batts or layers can be formed by winding the bulked yarnonto rolls, drums or forms at any desirable shape or by lacing the yarnin a fiat plane under tension until a suflicient thickness has beenachieved. Release of tension on the layer will then allow the yarnfilaments to contract to form a tightly interlocked, l ighly lofted,nonwoven batt. The resilience of the batt due to the coil filamentspermits it to be crushed and to then recover its thickness when thepressure is removed. The filaments can further be locked together bytreating the batt with steam or heated air, while a treatment of latexor some type of resinous binder can make a permanent structure.

The process of the present invention can thus be used to form non-Wovenbatts as well as the texturized or bulk yarn. The bulking operationworks as well on multifilament yarn as on monofilament. Eithermonofilament or multifilarnent yarn can be used to form the nonwovenbatts. Also, the process is successful on filaments of widely differentcross sectional configurations. For example, round, triangular andY-shaped filaments have The denier of the filaments is not importantexcept that with smaller denier, smaller helixes can be formed.

The fact that one side of the filament is heated to or above itssoftening point while the other side is cooled results in a texturizingor bulking of the yarn, the degree or amount of texturizing beingdependent upon the yarn temperature differential under a given yarntension. The relatively cool roll 17 in contact with the yarnfilament-ts serves as a heat sink to prevent an undesired temperaturerise in one side of the filaments. Thus, one side of each filament iscool relative to the other side.

The fact that heat is applied to the yarn at one point, rather thanalong a length of yarn, insures a superior result. This is because oneside of the filament is heated to a high degree while the other side iskept relatively cool. If the yarn is heated along a length it is likelythat, because of a twisting of the yarn under tension, portions of i theyarn will be heated to equal degrees on both sidesresulting in notexturizing. It is well known that a yarn under tension may twist orturn slightly as it is advanced. If this twist occurs in the span orlength of yarn which is being heated (as where the yarn passes over aheated moving belt), it may well result that both sides of the filamentare heated to equal temperaturesone side being heated before the twistand the other side after the twist. By heating the yarn at a singlepoint, this disadvantage is overcome.

It is to be understood that the process-disclosed herein may be modifiedor that other embodiments may be contemplated without departing from thespirit and scope of the invention.

What is claimed is:

1. The method of treating a synthetic textile filament, comprisingpassing the filament through a treating zone under tension, andsimultaneously heating and cooling opposite sides of the filament insaid zone, said heating being done at substantially a point location insaid zone, said heating being sufficient to stress-relieve the heatedside of the filament.

2. The method of treating a synthetic textile filament, comp-risingplacing said filament under tension, and heating one side of thefilament to near its melting point while maintaining the other side ofthe filament at a low temperature, said heating being done atsubstantially a point location on said filament.

3. The method of treating a thermoplastic filament, comprising advancingthe filament under tension over a roll, and applying heat to the exposedside of the filament at a point location thereon to heat said exposedside to a sufficient temperature to stress-relieve said exposed side,said roll being maintained at a temperature beneath the stress-relieftemperature of the filament.

4. The method of texturizing a thermoplastic yarn, comprising advancingthe yarn over a heat-sink element, and applying a stream of heated gasto the exposed side of the yarn at a point thereon to heat said exposedside to a temperature suflicient to stress-relieve said exposed side,said heat-sink element being cooled sufiiciently to maintain the otherside of the yarn at a temperature below said stress-relief temperature.

5. The method of texturizing 'a thermoplastic yarn, comp-risingadvancing the yarn across a heat-absorbing element at a speed within therange of 500-1500 feet per minute, and directing onto the yarn at theheat-absorbing element a stream of gas heated to a temperature withinthe range of 600-1100 F., said stream of gas being applied to the yarnat substantially a point location thereon.

6. The method of texturizing a thermoplastic yarn comprising advancingthe yarn under tension across a heatabsorbing element at a speed withinthe range of 500 1500 feet per minute, and applying a stream of gas tothe yarn at a point of engagement with the heat-absorbing element, saidstream of gas having a temperature sufliciently high to stress-relievethe exposed side of the filaments in the yarn, said heat-absorbingelement being cool enough to prevent stress-relief in the side of theyarn in engagement with said element.

References Cited by the Examiner UNITED STATES PATENTS 2,37 7,8 10 6/45Robbins 28-82 2,708,813 5/55 Bourgeaux 18-54 2,774,126 12/56 Secrist28--72.3 2,811,769 11/57 Craig 28-723 2,894,802 7/59 Braunlich 28--722,914,835 12/ 59 Slayter et al 28-72 2,917,805 12/59 Rokosz 28722,925,641 2/ 60 Evans 28-72 FOREIGN PATENTS 1,205,459 .8/59 France.

809,273 2/59 Great Britain.

MERVIN STEIN, Primary Examiner.

RUSSELL C. MADER, DONALD W. PARKER,

Examiners.

1. THE METHOD OF TREATING A SYNTHETIC TEXTILE FILAMENT, COMPRISINGPASSING THE FILAMENT THROUGH A TREATING ZONE UNDER TENSION, ANDSIMULTANEOUSLY HEATING AND COOLING OPPOSITE SIDES OF THE FILAMENT INSAID ZONE, SAID HEATING BEING DONE AT SUBSTANTIALLY A POINT LOCATION INSAID ZONE,